Airborne weather radar system may use a flat plate antenna mounted on a motorized, gimbaled mechanism installed in behind a radome in the nose of an aircraft. A flat plate antenna for weather radar may be a slotted array waveguide antennae constructed from aluminum. An aluminum slotted array waveguide antenna may have advantages because of low insertion loss, and good transmit and receive performance. Aluminum slotted array waveguide antennae have some disadvantages, which may include weight and high cost. Some of the high cost comes from the difficulty in manufacturing aluminum slotted array waveguide antennae because of multiple process steps, expensive braising techniques and a tendency to suffer from process variation. Small deviations in dimensions and positions of slots and other features may impact transmission and receiving performance. A weather radar system using an aluminum slotted array waveguide antennae may also require radar transmission and receive components mounted near the antenna, but not necessarily on the movable portion of the motorized mechanism. The system may also require waveguides to conduct the radio-frequency (RF) energy to and from the antenna. These waveguides may also be of aluminum or similar material, and built to very precise dimensions for proper RF performance. The material and precision manufacturing may also contribute to the weight and high cost of such a weather radar system. Costly and heavy weather radar systems may preclude their use on smaller aircraft.